1. Field of the Invention
This invention relates to an artificial knee joint, and more particularly to an artificial knee joint that includes a gripping member, which is movable to press against a rotating shaft so as to prevent relative rotation of a residual thigh of a prosthesis wearer and a prosthetic lower leg.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional artificial knee joint is shown to include an upper seat 6 adapted to be connected fixedly to a residual thigh (not shown) of a prosthesis wearer, a driving device 7, and a lower seat 8 connected to the upper seat 6 by the driving device 7 and adapted to be connected fixedly to a prosthetic lower leg 9. The lower seat 8 is configured as a hydraulic cylinder, and is provided with two pistons 81 so as to retard relative movement of the upper and lower seats 6, 8.
When the prosthesis wearer walks on a planar ground surface, the residual thigh can be raised to separate the prosthetic lower leg 9 from the planar ground surface such that the prosthetic lower leg 9 is inclined relative to the residual thigh, as shown in FIG. 1. Subsequently, the residual thigh is moved frontwardly and downwardly to permit the prosthetic lower leg 9 to contact the planar ground surface such that the prosthetic lower leg 9 is aligned with the residual thigh. As such, the prosthetic lower leg 9 can support the residual thigh on the planar ground surface.
Referring to FIG. 3, when the prosthesis wearer walks on an inclined ground surface, it is difficult to raise the residual thigh to a sufficient height to permit the prosthetic lower leg 9 to align with the residual thigh when the prosthetic lower leg 9 is moved downwardly to contact the inclined ground surface. As such, the prosthesis wearer may fall down due to the fact that a downward force and an upward force are applied respectively to the residual thigh and the prosthetic lower leg 9.